Estrogen Treatment for Transgender Women and Transfeminine People

Balancing the risks and benefits

Transgender women and transfeminine people are people whose assigned sex at birth is male, yet they exist as women. Transgender people represent a group that includes not just transgender women but also non- people who have a more feminine gender identity than the one that is expected for their recorded sex at birth. The term "transfeminine" is an umbrella term that encompasses both transgender women and feminine people of nonbinary identity. Many transgender people experience what is known as gender dysphoria—this is discomfort caused by people's bodies not matching their sense of identity.

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Not every transgender person deals with their gender dysphoria in the same way. However, for many people, hormone therapy can help them feel more like themselves. For transmasculine people, this involves testosterone treatment. For transfeminine people, this usually involves a combination of testosterone blockers and estrogen treatment.

Effects of Estrogen Treatment

Testosterone blockers are a necessary part of estrogen treatment for transfeminine people because testosterone acts more strongly in the body than estrogen does. Therefore, in order for transfeminine people to experience the effects of estrogen treatment, they must block their testosterone. The most common medication used to block testosterone is spironolactone or "spiro." Some also have their testicles removed (orchiectomy) so that they can take a lower dose of estrogen and not need a testosterone blocker.

The purpose of estrogen treatment for transfeminine people is to cause physical changes that make the body more feminine. The combination of a testosterone blocker with estrogen can lead to the following types of desired changes in the body:

  • breast growth
  • decreased body and facial hair
  • redistribution of body fat
  • softening and smoothing of the skin
  • reduced acne
  • slowed or stopped scalp balding

All of these are changes that can reduce gender dysphoria and improve quality of life. There are also some changes that occur that are less obvious. Some of these, like a reduction in testosterone, fewer penile erections, and a decline in blood pressure are generally considered to be positive changes. Others, like decreased sex drive and changes in cholesterol and other cardiovascular factors, may be less desirable.

The physical changes associated with estrogen treatment may start within a few months. However, changes can take two to three years to be fully realized. This is particularly true for breast growth. As many as two-thirds of transgender women and transfeminine people are not satisfied with breast growth and may seek breast augmentation. Research suggests that this procedure depends on a number of factors including when hormone treatment is started and how fully testosterone is suppressed.

Methods for Taking Estrogen

Estrogen can be taken in a number of different ways. People receive estrogen through a pill, injection, patch, or even a topical cream. It's not just a matter of preference. The route by which people take estrogen affects some of the risks of estrogen treatment—estrogen is absorbed by the body differently depending on how you take it.

Much of the research on the risks of estrogen treatment focus on oral estrogens—those taken by mouth. What research has found is that oral estrogen seems to cause an increased risk of a number of problematic side effects when compared to topical or injected estrogens. This is because of the effects of ingested estrogen on the liver when it passes through that organ during the process of digestion.

This is referred to as the hepatic first pass effect and it is not an issue for estrogen treatment that isn't taken in pill form. The hepatic first pass effect causes changes in a number of physiological markers that affect cardiovascular health.

These changes may lead to an increase in blood clotting and reduced cardiovascular health. They are not seen as often, if at all, with non-oral estrogens. Therefore, non-oral estrogens may be a safer option.

It is important to note that much of the research on the safety of estrogen treatment has been done in cisgender women taking oral contraceptives or hormone replacement therapy. This is potentially problematic as many of these treatments also contain progesterone, and the type of progesterone in these formulations has also been shown to affect the risk of cardiovascular disease. Transgender women and transfeminine people do not usually receive progesterone treatment.

Types of Estrogens

In addition to the different routes of administration of estrogen treatment, there are also different types of estrogens used for treatment. These include:

  • oral 17B-estradiol
  • oral conjugated estrogens
  • 17B-Estradiol patch (usually replaced every three to five days)
  • estradiol valerate injection (typically every two weeks)
  • estradiol cypionate injection (every one to two weeks)

Endocrine Society guidelines specifically suggest that oral ethinyl estradiol should not be used in transfeminine people. This is because oral ethinyl estradiol is the treatment most associated with thromboembolic events such as deep vein thrombosis, heart attack, pulmonary embolism, and stroke.

No matter what type of estrogen treatment is used, monitoring is important. The doctor who prescribes your estrogen should monitor the levels of estrogen in your blood.

The goal is to make certain you have similar levels of estrogen to premenopausal cisgender women, which is about 100 to 200 picograms/milliliter (pg/mL). A doctor will also need to monitor the effects of your anti-androgen by checking your testosterone levels.

The testosterone levels should also be the same as for premenopausal cisgender women (less than 50 nanograms per deciliter). However, androgen levels that are too low may lead to depression and generally feeling less well.

Risks and Benefits

By Route of Administration

In general, topical or injected estrogen treatment is thought to be safer than oral treatment. This is because there is no hepatic first pass effect. Topical and injectable estrogens also need to be taken less often, which may make dealing with them easier. However, there are downsides to these options as well.

It is easier for people to maintain steady levels of estrogen on pills than with other forms of estrogen. This can affect how some people feel when taking hormone treatment. Since levels of estrogen peak and then decline with injections and transdermal (patch/cream) formulations, it can also be harder for doctors to figure out the right level to prescribe.

In addition, some people experience skin rashes and irritation from estrogen patches. Estrogen creams can be difficult to deal with for people who live with others who might be exposed by touching treated skin. Injections may require visiting the doctor regularly for people who are not comfortable giving them to themselves.

By Type of Estrogen

Oral ethinyl estradiol is not recommended for use in transgender women because it is associated with an increased risk of blood clots. Conjugated estrogens are not used frequently, as they may put women at a higher risk of blood clots and heart attacks than 17B-estradiol, and they also cannot be accurately monitored with blood tests.

Risk of thrombosis (blood clots) is particularly high for those who smoke. Therefore, it is recommended that smokers always be put on transdermal 17B-estradiol, if that is an option.

Treatment and Gender Surgery

Currently, most surgeons recommend that transgender women and transfeminine people stop taking estrogen before they undergo gender affirmation surgery. This is because of the potentially increased risk for blood clots that is caused both by estrogen and by being inactive after surgery. However, it is unclear whether this recommendation is necessary for everyone.

Transgender women and nonbinary feminine people who are considering surgery should discuss the risks and benefits of discontinuing their estrogen treatment with their surgeon. For some, discontinuing estrogen is no big deal. For others, it can be extremely stressful and cause an increase in dysphoria. For such people, surgical concerns about blood clotting may be manageable using postoperative thromboprophylaxis. (This is a type of medical treatment that reduces the risk of clot formation.)

However, individual risks depend on a number of factors including the type of estrogen, smoking status, type of surgery, and other health concerns. It is important that this be a collaborative conversation with a doctor. For some, discontinuing estrogen treatment may be unavoidable. For others, risks may be managed in other ways.

A Word From Verywell

Transgender women and nonbinary feminine people taking estrogen treatment should be aware that they will need many of the same screening tests as cisgender women. In particular, they should follow the same screening guidelines for mammograms. This is because their breast cancer risk is much more similar to cisgender women than it is to cisgender men.

On the other hand, transgender women and feminine people on estrogen don't need to be screened for prostate cancer until after they turn 50. Prostate cancer appears to be quite rare in transfeminine people who have undergone a medical transition. This may be because of the reduced testosterone in their blood.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Hembree WC, Cohen-Kettenis PT, Gooren L, et al. Endocrine treatment of gender-dysphoric/gender-incongruent persons: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2017;102(11):3869-903. doi:10.1210/jc.2017-01658

  2. Seal LJ, Franklin S, Richards C, Shishkareva A, Sinclaire C, Barrett J. Predictive markers for mammoplasty and a comparison of side effect profiles in transwomen taking various hormonal regimens. J Clin Endocrinol Metab. 2012;97(12):4422-8. doi:10.1210/jc.2012-2030

  3. Boskey ER, Taghinia AH, Ganor O. Association of surgical risk with exogenous hormone use in transgender patients: a systematic review. JAMA Surg. 2019;154(2):159-69. doi:10.1001/jamasurg.2018.4598

  4. Tangpricha V, den Heijer M. Oestrogen and anti-androgen therapy for transgender women. Lancet Diabetes Endocrinol. 2017;5(4):291-300. doi:10.1016/S2213-8587(16)30319-9

Additional Reading
  • Streed CG Jr, Harfouch O, Marvel F, Blumenthal RS, Martin SS, Mukherjee M. Cardiovascular disease among transgender adults receiving hormone therapy: a narrative review. Ann Intern Med. 2017;167(4):256-67. doi:10.7326/M17-0577

By Elizabeth Boskey, PhD
Elizabeth Boskey, PhD, MPH, CHES, is a social worker, adjunct lecturer, and expert writer in the field of sexually transmitted diseases.